Almost all U.S. LTL carriers use NMFC freight classes, although some are attempting to move to a dimensionally-based system.
Freight class 50 is the least expensive because it refers to the freight that is easiest to transport for the carriers.
NMFC freight subclasses are used to differentiate among commodities of the same type. For example, one NMFC code for chairs/stools is 82790. Subclasses 82790-1 and 82790-11, despite have the same base NMFC code, fall into two different freight classes.